1. Field of the invention
The present invention relates to a sealed pushbutton switch, and particularly to a normally closed sealed pushbutton switch used in various electronic appliance.
2. Description of Related Art
A conventional sealed pushbutton switch is described in U.S. Pat. No. 6,459,057, which was issued on Oct. 1, 2002. The pushbutton switch is normally in a closed position, comprising a base, a plurality of fixed contacts assembled to the base, an insulative housing snapping onto the base, an actuator retained in the insulative housing and provided with a shaft and a head, a contact spring normally in contact with an inner edge of fixed contacts for establishing an electrical connection between the fixed contacts, a coil compression spring abutting against a bottom of the head, and an O-ring mounted around the shaft. In operation, the actuator is pushed downwardly to thereby move the contact spring away from the fixed contacts for breaking the electrical connection between the fixed contacts. The pushbutton switch is then caused to be in an open position.
The base is conglutinated to the insulative housing by glue or epoxy, which would creep into the insulative housing through some gaps defined between the base and the insulative housing. As a result, an operation of the detect switch would be adversely affected.
Hence, an improved pushbutton switch is required to overcome the above-mentioned disadvantages of the related art.